Collaboration Teams - Members share responsibility for posting refined answers to the guided readings - succinct, relevant, clear, and with pictures or a video to compliment.
When contributing to the reading guide, follow these steps: 1) First complete the reading guide on your own from the Nervous System unit page. 2) Write your response to a question in word and then copy it. Be sure to upload pictures and/or video for each question. 3) Click on the edit button and then go to the appropriate question and paste your answer below it.Sign your contribution with your first name and last initial and TEAM COLOR 4) Scroll to the very bottom and in the Optional comment box, place a summary of what you did and sign it (e.g. "I answered chp 26 question 3" - Tom S.) Th en click Save.
Collaboration Teams - Members share responsibility for posting refined answers to the guided readings - succinct, relevant, clear, and with pictures or a video to compliment.
Blue 1-5
Purple 6-10
Green 11-15
Pink 16-20
Yellow 21-25
Orange 26-30
Red 31-35
Brian
Jordan
Illian
Stephanie
Laura
Sawyer
Zach
Adam
Mario
Martin
Shyane
Alyssa
Amanda
Steve
Corinne
Keely
Jared
Jim
Dan
Sean
Jackie
Emily
Kim
AP Biology
Chapter 48 Guided Reading Assignment 1. What is a nerve net?
A nerve net is a web like system of nerves, characteristic of animals with bilateral symmetry. It is common in simple animal nervous systems such as cnidarians. The net goes all of the way through out animal.
http://www.saburchill.com/images05/0005.jpg
The cnidarians have one of the most easily seen nerve nets, with a bundle of nerves interconnected to each other forming the nerve net. 2. Compare and contrast the central and peripheral nervous systems. Both the central and peripheral nervous systems consists of a nervous system which uses sensory neurons, interneurons, and motor neurons, but their purposes are different. The central nervous system is where signals begin, at the brain and the spinal cord. The peripheral nervous system is responsible for the relaying of those signals to the rest of the body.
In this picture one can see the peripheral nervous system which branches off of the central nervous system. The central nervous system is the brain and the spinal cord.
Central Nervous System-- It includes the brain and the spinal cord. Peripheral Nervous System-- It is the sensory and motor neurons that connect to the Central Nervous System. Includes: sensory neurons, Nerves, Ganglion, plexus, motor functions and involuntary and voluntary muscle contractions (movement, breathing, and heart pumping)
3. How does the organization of the nervous system of a _ compare with the organization of the nervous system of a ?
a. Hydra and insect The hydra has a net-like Nervous System with nerves going all throughout the animal. Differently, the insect has a brain & a ventral nerve cord with nerves branching off of it going to the segments and the limbs of the insect. The insect has a Central and Peripheral Nervous System.
b. Hydra and flatworm The hydra has a net-like Nervous System with nerves going all throughout the animal where as the flatworm has a brain and two nerve cords that go down the sides of the worm with transverse nerves, forming a latter-like system with the nerve cords and it has a Central and Peripheral Nervous System. c. Leech and salamander The leech has a brain, a Central and Peripheral Nervous System along with a ventral nerve cord and segmented clusters of neurons called ganglia. The salamander has a brain and a dorsal spinal cord and the Peripheral Nervous System connects to the a Central Nervous System.
4. What are the functions of the following: a. Sensory neurons— A nerve cell that receives information form the internal and external environments and transmits the signals to the CNS. Such as pain, oder, light, sound, etc.
b. Interneurons—An association neuron; a nerve cell with in the central nervious system that forms synapses with sensory and motor neurons and integrates sensory input and motor output.
c. Motor neurons—A nerve cell that transmits signals between the brain and the spinal cord to the muscles or glands.
d. Effector cells—A muscle or gland cell that performs the body’s responces to stimuli; it responds to signals from the brain or other processing center of the Nervous System.
5. Why is it advantageous for the reflex response to circumvent instructions from the brain? Why might it be disadvantageous?
It is advantageous for the reflex response to skip instructions from the brain because with out a quick response, for example to the burning of skin by heat, lots of damage can be done to the skin. The quicker the reflex the less damage done, and it is much quicker to respond right away then to have a signal sent to the brain and then back down to respond. Yes it still happens fast but it is faster without the step of going to the brain. This reflex could also be disadvantageous because without thinking one may react to a stimulus when they actually want what ever is occurring to them to occur 6. Describe the path of a nerve signal below. The general direction of the nerve signal is from the presynaptic cell to the post synaptic cell. The presynaptic cell receives the signal through its dendrites. The signal travels through the cell body, which contains the nucleus. It then passes through the axon hillock and down the axon terminal, which is covered with myelin sheath. The signal is then passed through the synapse to the postsynaptic cell, and the process continues. -Laura C (purple team) 7. Why are glial cells important?
glial cells are important because they are supporting cells. They are essential fro the structural integrity of the nervous system and for the normal functioning of neurons. They outnumber neurons in the mammal brain
Zack B. Purple team
8. What are astrocytes? Found in CNS. Provide structural support for neurons. Regulate the extracellular concentrations of ions and neurotransmitters. Some respond to activity in neighboring neurons by facilitating information transfer at those neurons’ synapses. May be part of learning and memory. Astrocytes adjacent to active neurons cause nearby blood vessels to dilate, which increases blood flow to the area, enabling the neurons to obtain oxygen and glucose more quickly. -Laura C
9. What is the blood brain barrier and why is it important?
the development astrocytes induce the formation of tight junctions between cells and that lines the capillaries in the brain and spinal cord which creates the blood brain barrier. This is important because it restricts the passage of most substances into the CNS allowing the extracellular chemical environment of the CNS to be tightly controlled
Zack B. Purple team
10. Explain why myelin is important in nerve conduction?
Electrical impulses travel down a bare axon in a steady wave. When myelinated, an axon can convey electrical signals much quicker. Impulses "jump" from one myelin covering to another. This "jumping" is what allows the brain to communicate so quickly. Instead of traveling along the entire axon, impulses can just hop along. As a result, chemicals leave the axon terminals at a higher rate.
Sawyer W 11. Define the following terms:
a. Membrane potential
Membrane potential is the charge difference between a cell's cytoplasm and the extracellular fluid, due to the differential distribution of ions. - Shayne H. b. Resting potential Resting Potential is the membrane potential characteristic of a nonconducting, excitable cell, with the inside of the cell more negative than the outside.
- Shayne Huttick 12. Discuss the three types of gated ion channels below:
a. Ligand found at synapses and open or close when a specific chemical (i.e. neurotransmitter) binds to the channel.
found in axons, and open or close when the membrane potential changes.
c. Stretch cells that sense stretch and open when the membrane is mechanically deformed.
-Adam A 13. Define the following terms:
a. Hyperpolarization- An electrical state in which the inside of the cell is more negative relative to the outside than at the resting membrane potential. - b. Graded potentials- A local voltage change in a neuron membrane induced by stimulation of a neuron, with strength proportional to the strength of the stimulus and lasting about a millisecond. c. Depolarization- An electrical state in an excitable cell whereby the inside of the cell is made less negative relative to the outside than at the resting membrane potential. d. Threshold- The potential an excitable cell membrane must reach for an action potential to be initiated.
e. Action potential- A rapid change in the membrane potential of an excitable cell, caused by stimulus-triggered, selective opening and closing of voltage-sensitive gates in sodium and potassium ion channels.
- Shayne Huttick 14. Use the diagram to describe the generation of an action potential.
15. How do the various factors affect the speed of an action potential?
a. Larger axon
The wider the diameter of the axon the faster the conduction. Martin A
b. Myelination and salutatory conduction The myelin sheaths that cover the axons insulate them making them conduct faster. It is the same as enlarging the diameter of the axon. Saltatory conduction is when the inward current produced during the rising phase of the action potential at a node travels all the wat to the next node, where it depolarizes the membrane and generates a new action potential. The action potential seems to jump from node to node making the action potential go faster. Martin A
16. Use the diagram below to describe the conduction of the action potential.
-Amanda
17. What happens at the synaptic cleft?
action potential depolarizes membrane
opens Ca++ channels
neurotransmitter vesicles fuse with membrane
release neurotransmitter to synaptic cleft
neurotransmitter binds with protein receptor
ion-gated channels open
neurotransmitter degraded or reabsorbed
-Amanda 18. Contrast excitatory and inhibitory postsynaptic potentials.
The effect of excitatory postsynaphtic potentials is that the membrane potential is moved towards the threshold. The effect of inhibitory postsynaphtic potentials is that the membrane potential is moved away from the threshold. -Steve W.-
19. Contrast temporal and spatial summation.
Temporal summation is when two EPSP's occur in rapid succession from a single synapse. Spatial summation is when two EPSP's occur nearly sinultaneously from different synapses. -Steve W.-
20. What happens when indirect synaptic transmission takes place?
^^^ this video explains how neurotransmitters work!
a. Acetylcholine: one of the most common neurotransmitters in vertebrates and invertebrates. It is excitatory to vertebrate skeletal muscles. For example, at the vertebrate neuromuscular junction, the synapse between a motor neuron and a skeletal muscle cell, acetylcholine released by the motor neuron binds to the receptors on ligand-gated channels in the muscle cell, producing an EPSP via direct synaptic transmission.
b. Biogenic amines
i. Epinephrine and norepinephrine: Epinephrine and norepinephrine: types of biogenic amines derived from amino acids. They are in the group catecholamines produced from tyrosine. They also function as hormones.
ii. Dopamine : a biogenic amine closely related to epinephrine and norepinephrine. Dopamine, along with serotonin, is released at many sites in the brain and affects sleep, mood, attention, and learning.
iii. Serotonin : a biogenic amine synthesized from the amino acid tryptophan. Prozac enhances the effect of serotonin by inhibiting its uptake after release.
c. GABA : the neurotransmitter at most inhibitory synapses in the brain and produces IPSPs by increasing the permeability of the postsynaptic membrane to Cl-.
d. Endorphins : a neuropeptide that functions as a natural analgesic, decreasing pain perception. Opiates bind to receptors by mimicking endorphins, which are produced in the brain during times of physical or emotional stress, such as childbirth. It also decreases urine output by stimulating ADH secretion, depress respiration, produce euphoria, and have other emotional effects.
e. Nitrous oxide : a dissolved gas released by neurons of the vertebrate PNS and CNS which is released into the erectile tissue penis of a human male during sexual arousal. In response to the NO, smooth muscle cells relax, which causes the blood vessels to dilate and fill the spongy erectile tissue with blood, producing an erection. Unlike typical neurotransmitters, NO is not stored in cytoplasmic vesicles, cells synthesize it on demand.
22. What is the difference between gray matter and white matter?
Gray matter is regions of dendrites and clusters of neuron cell bodies within the CNS. White matter is tracks of axons within the CNS.
-Corinne DJ 23. Define the following terms:
a. Central nervous system: in vertebrate animals, the brain and spinal cord.
b. Peripheral nervous system : the sensory and motor neurons that connect to the central nervous system.
c. Somatic nervous system: the branch of the motor division of the vertebrate PNS composed of motor neurons that carry signals to skeletal muscles in response to external stimuli.
d. Autonomic nervous system : a subdivision of the motor nervous system of vertebrates that regulates the internal environment; consists of the sympathetic, parasympathetic, and enteric divisions. It controls smooth and cardiac muscles and the organs of the digestive, cardiovascular, excretory, and endocrine systems. This control is generally involuntary.
24. Contrast the core functions of the parasympathetic and sympathetic nervous system.
Activation of the sympathetic division corresponds to arousal and energy generation (the “fight-or-flight” response). For example, the heart beats faster, the liver converts glycogen to glucose, bronchi of the lungs dilate and support increased gas exchange, digestion is inhibited, and secretion of epinephrine from the adrenal medulla is stimulated. Activation of the parasympathetic division generally causes opposite responses that promote calming and a return to self-maintenance functions (“rest and digest”). For example, increased activity in this division decreases heart rate, increases glycogen production, and enhances digestion.
-Corinne DJ 25. What are the three brain regions during embryonic development?
The three bilaterally symmetrical, anterior bulges of the neural tube are the forebrain, the midbrain, and the hindbrain.
-Corinne DJ 26. What are the parts of the brainstem and what are its functions?
The medulla oblongata contains centers that control several visceral functions, including breathing, heart and blood vessel activity, swallowing, vomiting, and digestion. The pons also participates in some of these activities; for example, it regulates the breathing centers in the medulla. Information transmission is one of the most important functions of the medulla and pons. The midbrain contains centers for the receipt and integration of several types of sensory information. It also sends coded sensory information along neurons to specific regions of the forebrain. Prominent centers of the midbrain are the inferior and superior colliculi, which are part of the auditory and visual systems, respectively.
27. What is the reticular formation?
The reticular formation is a diffuse network of neurons containing over 90 separate clusters of cell bodies. It is present in the core of the brainstem. A part of the reticular formation, the reticular activating system (RAS) regulates sleep and arousal. Acting as a sensory filter, the RAS selects which information reaches the cerebral cortex, and the more information the cortex receives the more alert and aware a person is.
28. What are the core functions of the cerebellum
The cerebellum is important for coordination and error checking during motor, perceptual and cognitive functions. It is likely involved in learning and remembering motor skills, such as those involved in riding a bicycle. The cerebellum receives sensory information about the position of joints and the length of the muscles, as well as information from the auditory and visual systems. It also receives input concerning motor commands issued by the cerebrum. The cerebellum integrates this sensory and motor information as it coordinates movements and balance. Hand-eye coordination is an example of cerebellar control.
29. What are the parts of the diencephalon and what are its functions?
The embryonic diencephalon develops into three adult brain regions: the epithalamus, thalamus, and hypothalamus. The epithalamus includes the pineal gland and the choroid plexus, one of several clusters of capillaries that produce cerebrospinal fluid from blood. The thalamus is the main input center for sensory information going to the cerebrum and the main output center for motor information leaving the cerebrum. The hypothalamus is one of the most important brain regions for homeostatic regulation. They both are major integrating centers.
.
30. What are circadian rhythms?
Circadian Rhythms are biological or behavioral functions that vary over the course of a 24-hour day and are synchronized to light/dark daytime cycles and/or sleep/wakefulness.
31. Describe the cerebral hemispheres. The cerebral hemispheres are the right and left sides of the vertebrate brain. Each side consists of an outer covering of gray matter, the cerebral cortex, internal white matter and groups of neurons collectively called basal nuclei. The right hemisphere specializes in visual product communication and collaboration whereas the left hemisphere focuses on logical thinking, analysis, and accuracy. – Jackie H. Red team.
32. What is the corpus callosum? The corpus callosum is a thick band of nerve fibers that connect the right and left cerebral hemispheres, enabling the hemispheres to process information together. – Jackie H. Red team.
33. What is the limbic system and what is its function? The limbic system is a group of nuclei (clusters of nerve cell bodies) in the lower part of the mammalian forebrain that interacts with the cerebral cortex in determining emotions. It includes the hippocampus and amygdala. Jackie H. – Red team.
Skim ahead to Ch 49 and try to answer these:
34. Explain how the nervous system produces graded contractions of whole muscles.
Normaly, the action potential of a muscle fiber produces a quick contraction or twitch, but in most situations, the contraction is graded, meaning we can control its stength. The nervous system does this in two ways: it varies the number of fibers that contract and varies the rate at which the muscle fibers are stimulated. In most cases, each muscle fiber has only one motor neuron, but each branch might sinapse with multiple muscle fabers.
35. Labeling the diagram below, explain how a muscle contraction is controlled. F
irst, ACh is released by synaptic terminal diffusees across the synaptic cleft and binds to receptro proteins on the muscle fibers plansma membran, causing action potential, which is propogated along the plasma membrane and down T tubules. Then the action potential triggers Ca2+ release from sacroplasmic reticulum. The calcium ions then bind to troponin which changes shape and removes the blocking tropomyosin. Myosin cross bridges then alternately attach to actin and detach, pulling actin filaments toward center of sarcomere, all powered by ATP. Following that, calcium in the cytosol is removed by active transport back into the SR and tropomyosin blockage of myosin binding sites is restored, so contraction ends.
When contributing to the reading guide, follow these steps:
1) First complete the reading guide on your own from the Nervous System unit page.
2) Write your response to a question in word and then copy it. Be sure to upload pictures and/or video for each question.
3) Click on the edit button and then go to the appropriate question and paste your answer below it. Sign your contribution with your first name and last initial and TEAM COLOR
4) Scroll to the very bottom and in the Optional comment box, place a summary of what you did and sign it (e.g. "I answered chp 26 question 3" - Tom S.) Th en click Save.
Collaboration Teams - Members share responsibility for posting refined answers to the guided readings - succinct, relevant, clear, and with pictures or a video to compliment.Jordan
Illian
Laura
Sawyer
Zach
Mario
Martin
Shyane
Amanda
Steve
Keely
Jared
Dan
Sean
Emily
Kim
AP Biology
Chapter 48 Guided Reading Assignment
1. What is a nerve net?
A nerve net is a web like system of nerves, characteristic of animals with bilateral symmetry. It is common in simple animal nervous systems such as cnidarians. The net goes all of the way through out animal.
The cnidarians have one of the most easily seen nerve nets, with a bundle of nerves interconnected to each other forming the nerve net.
2. Compare and contrast the central and peripheral nervous systems.
Both the central and peripheral nervous systems consists of a nervous system which uses sensory neurons, interneurons, and motor neurons, but their purposes are different. The central nervous system is where signals begin, at the brain and the spinal cord. The peripheral nervous system is responsible for the relaying of those signals to the rest of the body.
In this picture one can see the peripheral nervous system which branches off of the central nervous system. The central nervous system is the brain and the spinal cord.
Central Nervous System-- It includes the brain and the spinal cord.
Peripheral Nervous System-- It is the sensory and motor neurons that connect to the Central Nervous System. Includes: sensory neurons, Nerves, Ganglion, plexus, motor functions and involuntary and voluntary muscle contractions (movement, breathing, and heart pumping)
3. How does the organization of the nervous system of a _ compare with the organization of the nervous system of a ?
a. Hydra and insect
The hydra has a net-like Nervous System with nerves going all throughout the animal. Differently, the insect has a brain & a ventral nerve cord with nerves branching off of it going to the segments and the limbs of the insect. The insect has a Central and Peripheral Nervous System.
b. Hydra and flatworm
The hydra has a net-like Nervous System with nerves going all throughout the animal where as the flatworm has a brain and two nerve cords that go down the sides of the worm with transverse nerves, forming a latter-like system with the nerve cords and it has a Central and Peripheral Nervous System.
c. Leech and salamander
The leech has a brain, a Central and Peripheral Nervous System along with a ventral nerve cord and segmented clusters of neurons called ganglia. The salamander has a brain and a dorsal spinal cord and the Peripheral Nervous System connects to the a Central Nervous System.
4. What are the functions of the following:
a. Sensory neurons— A nerve cell that receives information form the internal and external environments and transmits the signals to the CNS. Such as pain, oder, light, sound, etc.
b. Interneurons—An association neuron; a nerve cell with in the central nervious system that forms synapses with sensory and motor neurons and integrates sensory input and motor output.
c. Motor neurons—A nerve cell that transmits signals between the brain and the spinal cord to the muscles or glands.
d. Effector cells—A muscle or gland cell that performs the body’s responces to stimuli; it responds to signals from the brain or other processing center of the Nervous System.
5. Why is it advantageous for the reflex response to circumvent instructions from the brain? Why might it be disadvantageous?
It is advantageous for the reflex response to skip instructions from the brain because with out a quick response, for example to the burning of skin by heat, lots of damage can be done to the skin. The quicker the reflex the less damage done, and it is much quicker to respond right away then to have a signal sent to the brain and then back down to respond. Yes it still happens fast but it is faster without the step of going to the brain. This reflex could also be disadvantageous because without thinking one may react to a stimulus when they actually want what ever is occurring to them to occur
6. Describe the path of a nerve signal below.
The general direction of the nerve signal is from the presynaptic cell to the post synaptic cell. The presynaptic cell receives the signal through its dendrites. The signal travels through the cell body, which contains the nucleus. It then passes through the axon hillock and down the axon terminal, which is covered with myelin sheath. The signal is then passed through the synapse to the postsynaptic cell, and the process continues. -Laura C (purple team)
7. Why are glial cells important?
glial cells are important because they are supporting cells. They are essential fro the structural integrity of the nervous system and for the normal functioning of neurons. They outnumber neurons in the mammal brain
Zack B. Purple team
8. What are astrocytes?
Found in CNS. Provide structural support for neurons. Regulate the extracellular concentrations of ions and neurotransmitters. Some respond to activity in neighboring neurons by facilitating information transfer at those neurons’ synapses. May be part of learning and memory. Astrocytes adjacent to active neurons cause nearby blood vessels to dilate, which increases blood flow to the area, enabling the neurons to obtain oxygen and glucose more quickly. -Laura C
9. What is the blood brain barrier and why is it important?
the development astrocytes induce the formation of tight junctions between cells and that lines the capillaries in the brain and spinal cord which creates the blood brain barrier. This is important because it restricts the passage of most substances into the CNS allowing the extracellular chemical environment of the CNS to be tightly controlled
Zack B. Purple team
10. Explain why myelin is important in nerve conduction?
Electrical impulses travel down a bare axon in a steady wave. When myelinated, an axon can convey electrical signals much quicker. Impulses "jump" from one myelin covering to another. This "jumping" is what allows the brain to communicate so quickly. Instead of traveling along the entire axon, impulses can just hop along. As a result, chemicals leave the axon terminals at a higher rate.
Sawyer W
11. Define the following terms:
a. Membrane potential
Membrane potential is the charge difference between a cell's cytoplasm and the extracellular fluid, due to the differential distribution of ions. - Shayne H.
b. Resting potential
Resting Potential is the membrane potential characteristic of a nonconducting, excitable cell, with the inside of the cell more negative than the outside.
- Shayne Huttick
12. Discuss the three types of gated ion channels below:
a. Ligand
found at synapses and open or close when a specific chemical (i.e. neurotransmitter) binds to the channel.
b. Voltage
found in axons, and open or close when the membrane potential changes.
c. Stretch
cells that sense stretch and open when the membrane is mechanically deformed.
-Adam A
13. Define the following terms:
a. Hyperpolarization-
An electrical state in which the inside of the cell is more negative relative to the outside than at the resting membrane potential. - b. Graded potentials-
A local voltage change in a neuron membrane induced by stimulation of a neuron, with strength proportional to the strength of the stimulus and lasting about a millisecond.
c. Depolarization-
An electrical state in an excitable cell whereby the inside of the cell is made less negative relative to the outside than at the resting membrane potential.
d. Threshold-
The potential an excitable cell membrane must reach for an action potential to be initiated.
e. Action potential-
A rapid change in the membrane potential of an excitable cell, caused by stimulus-triggered, selective opening and closing of voltage-sensitive gates in sodium and potassium ion channels.
- Shayne Huttick
14. Use the diagram to describe the generation of an action potential.
15. How do the various factors affect the speed of an action potential?
a. Larger axon
The wider the diameter of the axon the faster the conduction. Martin A
b. Myelination and salutatory conduction
The myelin sheaths that cover the axons insulate them making them conduct faster. It is the same as enlarging the diameter of the axon. Saltatory conduction is when the inward current produced during the rising phase of the action potential at a node travels all the wat to the next node, where it depolarizes the membrane and generates a new action potential. The action potential seems to jump from node to node making the action potential go faster. Martin A
16. Use the diagram below to describe the conduction of the action potential.
-Amanda
17. What happens at the synaptic cleft?
- action potential depolarizes membrane
- opens Ca++ channels
- neurotransmitter vesicles fuse with membrane
- release neurotransmitter to synaptic cleft
- neurotransmitter binds with protein receptor
- ion-gated channels open
- neurotransmitter degraded or reabsorbed
-Amanda18. Contrast excitatory and inhibitory postsynaptic potentials.
The effect of excitatory postsynaphtic potentials is that the membrane potential is moved towards the threshold. The effect of inhibitory postsynaphtic potentials is that the membrane potential is moved away from the threshold. -Steve W.-
19. Contrast temporal and spatial summation.
Temporal summation is when two EPSP's occur in rapid succession from a single synapse. Spatial summation is when two EPSP's occur nearly sinultaneously from different synapses. -Steve W.-
20. What happens when indirect synaptic transmission takes place?
21. Discuss the neurotransmitters listed below:
Neurotransmitters
^^^ this video explains how neurotransmitters work!
a. Acetylcholine:
one of the most common neurotransmitters in vertebrates and invertebrates. It is excitatory to vertebrate skeletal muscles. For example, at the vertebrate neuromuscular junction, the synapse between a motor neuron and a skeletal muscle cell, acetylcholine released by the motor neuron binds to the receptors on ligand-gated channels in the muscle cell, producing an EPSP via direct synaptic transmission.
b. Biogenic amines
i. Epinephrine and norepinephrine:
Epinephrine and norepinephrine: types of biogenic amines derived from amino acids. They are in the group catecholamines produced from tyrosine. They also function as hormones.
ii. Dopamine
: a biogenic amine closely related to epinephrine and norepinephrine. Dopamine, along with serotonin, is released at many sites in the brain and affects sleep, mood, attention, and learning.
iii. Serotonin
: a biogenic amine synthesized from the amino acid tryptophan. Prozac enhances the effect of serotonin by inhibiting its uptake after release.
c. GABA
: the neurotransmitter at most inhibitory synapses in the brain and produces IPSPs by increasing the permeability of the postsynaptic membrane to Cl-.
d. Endorphins
: a neuropeptide that functions as a natural analgesic, decreasing pain perception. Opiates bind to receptors by mimicking endorphins, which are produced in the brain during times of physical or emotional stress, such as childbirth. It also decreases urine output by stimulating ADH secretion, depress respiration, produce euphoria, and have other emotional effects.
e. Nitrous oxide
: a dissolved gas released by neurons of the vertebrate PNS and CNS which is released into the erectile tissue penis of a human male during sexual arousal. In response to the NO, smooth muscle cells relax, which causes the blood vessels to dilate and fill the spongy erectile tissue with blood, producing an erection. Unlike typical neurotransmitters, NO is not stored in cytoplasmic vesicles, cells synthesize it on demand.
22. What is the difference between gray matter and white matter?
Gray matter is regions of dendrites and clusters of neuron cell bodies within the CNS. White matter is tracks of axons within the CNS.
-Corinne DJ
23. Define the following terms:
a. Central nervous system:
in vertebrate animals, the brain and spinal cord.
b. Peripheral nervous system
: the sensory and motor neurons that connect to the central nervous system.
c. Somatic nervous system:
the branch of the motor division of the vertebrate PNS composed of motor neurons that carry signals to skeletal muscles in response to external stimuli.
d. Autonomic nervous system
: a subdivision of the motor nervous system of vertebrates that regulates the internal environment; consists of the sympathetic, parasympathetic, and enteric divisions. It controls smooth and
cardiac muscles and the organs of the digestive, cardiovascular, excretory, and endocrine systems. This control is generally involuntary.
24. Contrast the core functions of the parasympathetic and sympathetic nervous system.
Activation of the sympathetic division corresponds to arousal and energy generation (the “fight-or-flight” response). For example, the heart beats faster, the liver converts glycogen to glucose, bronchi of the lungs dilate and support increased gas exchange, digestion is inhibited, and secretion of epinephrine from the adrenal medulla is stimulated. Activation of the parasympathetic division generally causes opposite responses that promote calming and a return to self-maintenance functions (“rest and digest”). For example, increased activity in this division decreases heart rate, increases glycogen production, and enhances digestion.
-Corinne DJ
25. What are the three brain regions during embryonic development?
The three bilaterally symmetrical, anterior bulges of the neural tube are the forebrain, the midbrain, and the hindbrain.
-Corinne DJ
26. What are the parts of the brainstem and what are its functions?
The medulla oblongata contains centers that control several visceral functions, including breathing, heart and blood vessel activity, swallowing, vomiting, and digestion. The pons also participates in some of these activities; for example, it regulates the breathing centers in the medulla. Information transmission is one of the most important functions of the medulla and pons. The midbrain contains centers for the receipt and integration of several types of sensory information. It also sends coded sensory information along neurons to specific regions of the forebrain. Prominent centers of the midbrain are the inferior and superior colliculi, which are part of the auditory and visual systems, respectively.
27. What is the reticular formation?
The reticular formation is a diffuse network of neurons containing over 90 separate clusters of cell bodies. It is present in the core of the brainstem. A part of the reticular formation, the reticular activating system (RAS) regulates sleep and arousal. Acting as a sensory filter, the RAS selects which information reaches the cerebral cortex, and the more information the cortex receives the more alert and aware a person is.
28. What are the core functions of the cerebellum
The cerebellum is important for coordination and error checking during motor, perceptual and cognitive functions. It is likely involved in learning and remembering motor skills, such as those involved in riding a bicycle. The cerebellum receives sensory information about the position of joints and the length of the muscles, as well as information from the auditory and visual systems. It also receives input concerning motor commands issued by the cerebrum. The cerebellum integrates this sensory and motor information as it coordinates movements and balance. Hand-eye coordination is an example of cerebellar control.
29. What are the parts of the diencephalon and what are its functions?
The embryonic diencephalon develops into three adult brain regions: the epithalamus, thalamus, and hypothalamus. The epithalamus includes the pineal gland and the choroid plexus, one of several clusters of capillaries that produce cerebrospinal fluid from blood. The thalamus is the main input center for sensory information going to the cerebrum and the main output center for motor information leaving the cerebrum. The hypothalamus is one of the most important brain regions for homeostatic regulation. They both are major integrating centers.
30. What are circadian rhythms?
Circadian Rhythms are biological or behavioral functions that vary over the course of a 24-hour day and are synchronized to light/dark daytime cycles and/or sleep/wakefulness.
31. Describe the cerebral hemispheres.
The cerebral hemispheres are the right and left sides of the vertebrate brain. Each side consists of an outer covering of gray matter, the cerebral cortex, internal white matter and groups of neurons collectively called basal nuclei. The right hemisphere specializes in visual product communication and collaboration whereas the left hemisphere focuses on logical thinking, analysis, and accuracy. – Jackie H. Red team.
32. What is the corpus callosum?
The corpus callosum is a thick band of nerve fibers that connect the right and left cerebral hemispheres, enabling the hemispheres to process information together. – Jackie H. Red team.
33. What is the limbic system and what is its function?
The limbic system is a group of nuclei (clusters of nerve cell bodies) in the lower part of the mammalian forebrain that interacts with the cerebral cortex in determining emotions. It includes the hippocampus and amygdala. Jackie H. – Red team.
Skim ahead to Ch 49 and try to answer these:
34. Explain how the nervous system produces graded contractions of whole muscles.
Normaly, the action potential of a muscle fiber produces a quick contraction or twitch, but in most situations, the contraction is graded, meaning we can control its stength. The nervous system does this in two ways: it varies the number of fibers that contract and varies the rate at which the muscle fibers are stimulated. In most cases, each muscle fiber has only one motor neuron, but each branch might sinapse with multiple muscle fabers.
35. Labeling the diagram below, explain how a muscle contraction is controlled.
irst, ACh is released by synaptic terminal diffusees across the synaptic cleft and binds to receptro proteins on the muscle fibers plansma membran, causing action potential, which is propogated along the plasma membrane and down T tubules. Then the action potential triggers Ca2+ release from sacroplasmic reticulum. The calcium ions then bind to troponin which changes shape and removes the blocking tropomyosin. Myosin cross bridges then alternately attach to actin and detach, pulling actin filaments toward center of sarcomere, all powered by ATP. Following that, calcium in the cytosol is removed by active transport back into the SR and tropomyosin blockage of myosin binding sites is restored, so contraction ends.